diff --git a/src/p_armpe.cpp b/src/p_armpe.cpp
index 66b8f2ef..ab2c90b0 100644
--- a/src/p_armpe.cpp
+++ b/src/p_armpe.cpp
@@ -1942,14 +1942,14 @@ void PackArmPe::pack(OutputFile *fo)
         identsplit = ALIGN_GAP(identsplit, 0x200);
     ic = identsize - identsplit;
 
-    const unsigned clen = ((ph.c_len + ic) & 15) == 0 ? ph.c_len : ph.c_len + 16 - ((ph.c_len + ic) & 15);
-    obuf.clear(ph.c_len, clen - ph.c_len);
+    const unsigned c_len = ((ph.c_len + ic) & 15) == 0 ? ph.c_len : ph.c_len + 16 - ((ph.c_len + ic) & 15);
+    obuf.clear(ph.c_len, c_len - ph.c_len);
 
-    const unsigned s1size = ALIGN_UP(ic + clen + codesize,4) + sotls;
-    const unsigned s1addr = (newvsize - (ic + clen) + oam1) &~ oam1;
+    const unsigned s1size = ALIGN_UP(ic + c_len + codesize,4) + sotls;
+    const unsigned s1addr = (newvsize - (ic + c_len) + oam1) &~ oam1;
 
     const unsigned ncsection = (s1addr + s1size + oam1) &~ oam1;
-    const unsigned upxsection = s1addr + ic + clen;
+    const unsigned upxsection = s1addr + ic + c_len;
 
     Reloc rel(1024); // new relocations are put here
     // patch loader
@@ -2101,8 +2101,8 @@ void PackArmPe::pack(OutputFile *fo)
     }
     fo->write(loader + codesize,identsize);
     infoWriting("loader", fo->getBytesWritten());
-    fo->write(obuf,clen);
-    infoWriting("compressed data", clen);
+    fo->write(obuf,c_len);
+    infoWriting("compressed data", c_len);
     fo->write(loader,codesize);
     if (opt->debug.dump_stub_loader)
         OutputFile::dump(opt->debug.dump_stub_loader, loader, codesize);
@@ -2123,7 +2123,7 @@ void PackArmPe::pack(OutputFile *fo)
     printf("%-13s: program hdr  : %8ld bytes\n", getName(), (long) sizeof(oh));
     printf("%-13s: sections     : %8ld bytes\n", getName(), (long) sizeof(osection));
     printf("%-13s: ident        : %8ld bytes\n", getName(), (long) identsize);
-    printf("%-13s: compressed   : %8ld bytes\n", getName(), (long) clen);
+    printf("%-13s: compressed   : %8ld bytes\n", getName(), (long) c_len);
     printf("%-13s: decompressor : %8ld bytes\n", getName(), (long) codesize);
     printf("%-13s: tls          : %8ld bytes\n", getName(), (long) sotls);
     printf("%-13s: resources    : %8ld bytes\n", getName(), (long) soresources);
diff --git a/src/p_exe.cpp b/src/p_exe.cpp
index 52c1c745..09fc790f 100644
--- a/src/p_exe.cpp
+++ b/src/p_exe.cpp
@@ -542,7 +542,7 @@ void PackExe::pack(OutputFile *fo)
         oh.ip = getLoaderSection("EXEENTRY") - 2;
     }
 
-//fprintf(stderr,"\ne_len=%x d_len=%x clen=%x oo=%x ulen=%x destp=%x copys=%x images=%x",e_len,d_len,packedsize,ph.overlap_overhead,ph.u_len,destpara,copysize,ih_imagesize);
+//fprintf(stderr,"\ne_len=%x d_len=%x c_len=%x oo=%x ulen=%x destp=%x copys=%x images=%x",e_len,d_len,packedsize,ph.overlap_overhead,ph.u_len,destpara,copysize,ih_imagesize);
 
     // write header + write loader + compressed file
 #ifdef TESTING
diff --git a/src/p_lx_elf.cpp b/src/p_lx_elf.cpp
index 6bccc8d7..25614543 100644
--- a/src/p_lx_elf.cpp
+++ b/src/p_lx_elf.cpp
@@ -968,7 +968,7 @@ void PackLinuxElf32::pack2(OutputFile *fo, Filter &ft)
     unsigned total_in = 0;
     unsigned total_out = 0;
 
-    unsigned hdr_ulen = sizeof(Elf32_Ehdr) + sz_phdrs;
+    unsigned hdr_u_len = sizeof(Elf32_Ehdr) + sz_phdrs;
 
     ui_pass = 0;
     ft.addvalue = 0;
@@ -993,8 +993,8 @@ void PackLinuxElf32::pack2(OutputFile *fo, Filter &ft)
         // sometimes marks as PF_X anyway.  So filter only first segment.
         packExtent(x, total_in, total_out,
             ((0==nx && (Elf32_Phdr::PF_X & get_native32(&phdri[k].p_flags)))
-                ? &ft : 0 ), fo, hdr_ulen);
-        hdr_ulen = 0;
+                ? &ft : 0 ), fo, hdr_u_len);
+        hdr_u_len = 0;
         ++nx;
     }
     for (k = 0; k < e_phnum; ++k) {
@@ -1070,7 +1070,7 @@ void PackLinuxElf64::pack2(OutputFile *fo, Filter &ft)
     unsigned total_in = 0;
     unsigned total_out = 0;
 
-    unsigned hdr_ulen = sizeof(Elf64_Ehdr) + sz_phdrs;
+    unsigned hdr_u_len = sizeof(Elf64_Ehdr) + sz_phdrs;
 
     ui_pass = 0;
     ft.addvalue = 0;
@@ -1095,8 +1095,8 @@ void PackLinuxElf64::pack2(OutputFile *fo, Filter &ft)
         // sometimes marks as PF_X anyway.  So filter only first segment.
         packExtent(x, total_in, total_out,
             ((0==nx && (Elf64_Phdr::PF_X & get_native64(&phdri[k].p_flags)))
-                ? &ft : 0 ), fo, hdr_ulen);
-        hdr_ulen = 0;
+                ? &ft : 0 ), fo, hdr_u_len);
+        hdr_u_len = 0;
         ++nx;
     }
     for (k = 0; k < e_phnum; ++k) {
diff --git a/src/p_mach.cpp b/src/p_mach.cpp
index 4b641289..1805fdc7 100644
--- a/src/p_mach.cpp
+++ b/src/p_mach.cpp
@@ -240,7 +240,7 @@ PackMachPPC32::pack2(OutputFile *fo, Filter &ft)  // append compressed body
     unsigned total_in = 0;
     unsigned total_out = 0;
 
-    unsigned hdr_ulen = mhdri.sizeofcmds;
+    unsigned hdr_u_len = mhdri.sizeofcmds;
 
     ui_pass = 0;
     ft.addvalue = 0;
@@ -258,8 +258,8 @@ PackMachPPC32::pack2(OutputFile *fo, Filter &ft)  // append compressed body
         }
         packExtent(x, total_in, total_out,
             ((Mach_segment_command::VM_PROT_EXECUTE & msegcmd[k].initprot)
-                ? &ft : 0 ), fo, hdr_ulen );
-        hdr_ulen = 0;
+                ? &ft : 0 ), fo, hdr_u_len );
+        hdr_u_len = 0;
         ++nx;
     }
     for (k = 0; k < n_segment; ++k) {
diff --git a/src/p_tmt.cpp b/src/p_tmt.cpp
index 447a1743..fbecbbac 100644
--- a/src/p_tmt.cpp
+++ b/src/p_tmt.cpp
@@ -249,7 +249,7 @@ void PackTmt::pack(OutputFile *fo)
     patch_le32(loader,e_len,"ECX0",ph.c_len+d_len);
     patch_le32(loader,e_len,"EDI0",ph.u_len+ph.overlap_overhead+d_len-1);
     patch_le32(loader,e_len,"ESI0",ph.c_len+e_len+d_len-1);
-    //fprintf(stderr,"\nelen=%x dlen=%x copy_len=%x  copy_to=%x  oo=%x  jmp_pos=%x  ulen=%x  clen=%x \n\n",
+    //fprintf(stderr,"\nelen=%x dlen=%x copy_len=%x  copy_to=%x  oo=%x  jmp_pos=%x  ulen=%x  c_len=%x \n\n",
     //                e_len,d_len,copy_len,copy_to,ph.overlap_overhead,jmp_pos,ph.u_len,ph.c_len);
 
     memcpy(&oh,&ih,sizeof(oh));
diff --git a/src/p_unix.cpp b/src/p_unix.cpp
index ddae4b25..aecd26d2 100644
--- a/src/p_unix.cpp
+++ b/src/p_unix.cpp
@@ -305,16 +305,16 @@ void PackUnix::packExtent(
     unsigned &total_out,
     Filter *ft,
     OutputFile *fo,
-    unsigned hdr_ulen
+    unsigned hdr_u_len
 )
 {
     unsigned const init_u_adler = ph.u_adler;
     unsigned const init_c_adler = ph.c_adler;
     MemBuffer hdr_ibuf;
-    if (hdr_ulen) {
-        hdr_ibuf.alloc(hdr_ulen);
+    if (hdr_u_len) {
+        hdr_ibuf.alloc(hdr_u_len);
         fi->seek(0, SEEK_SET);
-        int l = fi->readx(hdr_ibuf, hdr_ulen);
+        int l = fi->readx(hdr_ibuf, hdr_u_len);
         (void)l;
     }
     fi->seek(x.offset, SEEK_SET);
@@ -348,7 +348,7 @@ void PackUnix::packExtent(
 
             compressWithFilters(ft, OVERHEAD, strategy,
                 NULL, 0, 0, 0, 0, // those 5 args are the defaults
-                hdr_ibuf, hdr_ulen);
+                hdr_ibuf, hdr_u_len);
         }
         else {
             (void) compress(ibuf, obuf);    // ignore return value
@@ -371,31 +371,31 @@ void PackUnix::packExtent(
 
         // write block sizes
         b_info tmp;
-        if (hdr_ulen) {
-            unsigned hdr_clen;
+        if (hdr_u_len) {
+            unsigned hdr_c_len;
             MemBuffer hdr_obuf;
-            hdr_obuf.allocForCompression(hdr_ulen);
-            int r = upx_compress(hdr_ibuf, hdr_ulen, hdr_obuf, &hdr_clen, 0,
+            hdr_obuf.allocForCompression(hdr_u_len);
+            int r = upx_compress(hdr_ibuf, hdr_u_len, hdr_obuf, &hdr_c_len, 0,
                 ph.method, 10, NULL, NULL);
             if (r != UPX_E_OK)
                 throwInternalError("header compression failed");
-            if (hdr_clen >= hdr_ulen)
+            if (hdr_c_len >= hdr_u_len)
                 throwInternalError("header compression size increase");
-            ph.saved_u_adler = upx_adler32(hdr_ibuf, hdr_ulen, init_u_adler);
-            ph.saved_c_adler = upx_adler32(hdr_obuf, hdr_clen, init_c_adler);
+            ph.saved_u_adler = upx_adler32(hdr_ibuf, hdr_u_len, init_u_adler);
+            ph.saved_c_adler = upx_adler32(hdr_obuf, hdr_c_len, init_c_adler);
             ph.u_adler = upx_adler32(ibuf, ph.u_len, ph.saved_u_adler);
             ph.c_adler = upx_adler32(obuf, ph.c_len, ph.saved_c_adler);
             end_u_adler = ph.u_adler;
             memset(&tmp, 0, sizeof(tmp));
-            set_native32(&tmp.sz_unc, hdr_ulen);
-            set_native32(&tmp.sz_cpr, hdr_clen);
+            set_native32(&tmp.sz_unc, hdr_u_len);
+            set_native32(&tmp.sz_cpr, hdr_c_len);
             tmp.b_method = (unsigned char) ph.method;
             fo->write(&tmp, sizeof(tmp));
             b_len += sizeof(b_info);
-            fo->write(hdr_obuf, hdr_clen);
-            total_out += hdr_clen;
-            total_in  += hdr_ulen;
-            hdr_ulen = 0;  // compress hdr one time only
+            fo->write(hdr_obuf, hdr_c_len);
+            total_out += hdr_c_len;
+            total_in  += hdr_u_len;
+            hdr_u_len = 0;  // compress hdr one time only
         }
         memset(&tmp, 0, sizeof(tmp));
         set_native32(&tmp.sz_unc, ph.u_len);
diff --git a/src/p_vmlinz.cpp b/src/p_vmlinz.cpp
index 7937cf2b..859f1a0c 100644
--- a/src/p_vmlinz.cpp
+++ b/src/p_vmlinz.cpp
@@ -354,9 +354,9 @@ void PackBvmlinuzI386::pack(OutputFile *fo)
     compressWithFilters(&ft, 512);
 
     // align everything to dword boundary - it is easier to handle
-    unsigned clen = ph.c_len;
-    memset(obuf + clen, 0, 4);
-    clen = ALIGN_UP(clen, 4);
+    unsigned c_len = ph.c_len;
+    memset(obuf + c_len, 0, 4);
+    c_len = ALIGN_UP(c_len, 4);
 
     const unsigned lsize = getLoaderSize();
     MemBuffer loader(lsize);
@@ -370,14 +370,14 @@ void PackBvmlinuzI386::pack(OutputFile *fo)
 
     const unsigned d_len4 = ALIGN_UP(lsize - e_len, 4);
     const unsigned decompr_pos = ALIGN_UP(ph.u_len + ph.overlap_overhead, 16);
-    const unsigned copy_size = clen + d_len4;
+    const unsigned copy_size = c_len + d_len4;
     const unsigned edi = decompr_pos + d_len4 - 4;          // copy to
-    const unsigned esi = ALIGN_UP(clen + lsize, 4) - 4;     // copy from
+    const unsigned esi = ALIGN_UP(c_len + lsize, 4) - 4;     // copy from
 
     unsigned jpos = find_le32(loader, e_len, get_le32("JMPD"));
     patch_le32(loader, e_len, "JMPD", decompr_pos - jpos - 4);
 
-    patch_le32(loader, e_len, "ESI1", bzimage_offset + decompr_pos - clen);
+    patch_le32(loader, e_len, "ESI1", bzimage_offset + decompr_pos - c_len);
     patch_le32(loader, e_len, "ECX0", copy_size / 4);
     patch_le32(loader, e_len, "EDI0", bzimage_offset + edi);
     patch_le32(loader, e_len, "ESI0", bzimage_offset + esi);
@@ -389,16 +389,16 @@ void PackBvmlinuzI386::pack(OutputFile *fo)
     patch_le32(loader, e_len, "STAK", stack_offset_during_uncompression);
 
     boot_sect_t * const bs = (boot_sect_t *) ((unsigned char *) setup_buf);
-    bs->sys_size = (ALIGN_UP(lsize + clen, 16) / 16) & 0xffff;
+    bs->sys_size = (ALIGN_UP(lsize + c_len, 16) / 16) & 0xffff;
 
     fo->write(setup_buf, setup_buf.getSize());
     fo->write(loader, e_len);
-    fo->write(obuf, clen);
+    fo->write(obuf, c_len);
     fo->write(loader + e_len, lsize - e_len);
 #if 0
     printf("%-13s: setup        : %8ld bytes\n", getName(), (long) setup_buf.getSize());
     printf("%-13s: entry        : %8ld bytes\n", getName(), (long) e_len);
-    printf("%-13s: compressed   : %8ld bytes\n", getName(), (long) clen);
+    printf("%-13s: compressed   : %8ld bytes\n", getName(), (long) c_len);
     printf("%-13s: decompressor : %8ld bytes\n", getName(), (long) (lsize - e_len));
 #endif
 
diff --git a/src/p_w32pe.cpp b/src/p_w32pe.cpp
index 73157be3..f613fdb1 100644
--- a/src/p_w32pe.cpp
+++ b/src/p_w32pe.cpp
@@ -1954,14 +1954,14 @@ void PackW32Pe::pack(OutputFile *fo)
         identsplit = ALIGN_GAP(identsplit, 0x200);
     ic = identsize - identsplit;
 
-    const unsigned clen = ((ph.c_len + ic) & 15) == 0 ? ph.c_len : ph.c_len + 16 - ((ph.c_len + ic) & 15);
-    obuf.clear(ph.c_len, clen - ph.c_len);
+    const unsigned c_len = ((ph.c_len + ic) & 15) == 0 ? ph.c_len : ph.c_len + 16 - ((ph.c_len + ic) & 15);
+    obuf.clear(ph.c_len, c_len - ph.c_len);
 
-    const unsigned s1size = ALIGN_UP(ic + clen + codesize,4) + sotls;
-    const unsigned s1addr = (newvsize - (ic + clen) + oam1) &~ oam1;
+    const unsigned s1size = ALIGN_UP(ic + c_len + codesize,4) + sotls;
+    const unsigned s1addr = (newvsize - (ic + c_len) + oam1) &~ oam1;
 
     const unsigned ncsection = (s1addr + s1size + oam1) &~ oam1;
-    const unsigned upxsection = s1addr + ic + clen;
+    const unsigned upxsection = s1addr + ic + c_len;
     const unsigned myimport = ncsection + soresources - rvamin;
 
     // patch loader
@@ -2192,8 +2192,8 @@ void PackW32Pe::pack(OutputFile *fo)
     }
     fo->write(loader + codesize,identsize);
     infoWriting("loader", fo->getBytesWritten());
-    fo->write(obuf,clen);
-    infoWriting("compressed data", clen);
+    fo->write(obuf,c_len);
+    infoWriting("compressed data", c_len);
     fo->write(loader,codesize);
     if (opt->debug.dump_stub_loader)
         OutputFile::dump(opt->debug.dump_stub_loader, loader, codesize);
@@ -2215,7 +2215,7 @@ void PackW32Pe::pack(OutputFile *fo)
     printf("%-13s: program hdr  : %8ld bytes\n", getName(), (long) sizeof(oh));
     printf("%-13s: sections     : %8ld bytes\n", getName(), (long) sizeof(osection));
     printf("%-13s: ident        : %8ld bytes\n", getName(), (long) identsize);
-    printf("%-13s: compressed   : %8ld bytes\n", getName(), (long) clen);
+    printf("%-13s: compressed   : %8ld bytes\n", getName(), (long) c_len);
     printf("%-13s: decompressor : %8ld bytes\n", getName(), (long) codesize);
     printf("%-13s: tls          : %8ld bytes\n", getName(), (long) sotls);
     printf("%-13s: resources    : %8ld bytes\n", getName(), (long) soresources);