CODEWITHSUNDEEP
cname-mangling
gemneotrix
gemneotrix

Reputation: 21

Symbol name generated has additional leading underscore

I am having a MinGW compiler setup in windows. and having project setup where some third party *.a files are directly copied from Linux machine.

Tried compiling a simple C program and when I look into the symbol table of *.o file, it has leading underscore for all the symbol names.

Example program : 

int main(int argc, char** argv) 
{   
     int xyz=0; 
     printf("I am Here\n");
}

SymbolTable entry:

Sections:

Idx Name          Size      VMA       LMA       File off  Algn
  0 .text         00000040  00000000  00000000  0000008c  2**2
                  CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
  1 .data         00000000  00000000  00000000  00000000  2**2
                  ALLOC, LOAD, DATA
  2 .bss          00000000  00000000  00000000  00000000  2**2
                  ALLOC

SYMBOL TABLE:

[  0](sec -2)(fl 0x00)(ty   0)(scl 103) (nx 1) 0x00000000 abcd01.c
File
[  2](sec  1)(fl 0x00)(ty  20)(scl   2) (nx 0) 0x0000000b **_main**
[  3](sec  1)(fl 0x00)(ty   0)(scl   3) (nx 1) 0x00000000 .text
AUX scnlen 0x3e nreloc 4 nlnno 0
[  5](sec  2)(fl 0x00)(ty   0)(scl   3) (nx 1) 0x00000000 .data
AUX scnlen 0x0 nreloc 0 nlnno 0
[  7](sec  3)(fl 0x00)(ty   0)(scl   3) (nx 1) 0x00000000 .bss
AUX scnlen 0x0 nreloc 0 nlnno 0
[  9](sec  0)(fl 0x00)(ty  20)(scl   2) (nx 1) 0x00000000 ___main
AUX tagndx 0 ttlsiz 0x0 lnnos 0 next 0
[ 11](sec  0)(fl 0x00)(ty   0)(scl   2) (nx 0) 0x00000000 __alloca
[ 12](sec  0)(fl 0x00)(ty  20)(scl   2) (nx 0) 0x00000000 **_printf**

RELOCATION RECORDS FOR [.text]:

OFFSET   TYPE              VALUE
00000020 DISP32            __alloca
00000025 DISP32            ___main
00000033 dir32             .text
00000038 DISP32            **_printf**

Here even base C functions are prepended with underscore.

Tried using -fno-leading-underscore, but no use.

MingW version:

$ gcc -v
Reading specs from C:/PROGRA~1/GNUCFO~1//ncbin/../lib/gcc-lib/i386-pc-mks/3.3.1/
specs
Configured with: configure --prefix=/usr/gnu i386-pc-mks --enable-languages=c,c+
+ --disable-nls --disable-shared --enable-sjlj-exceptions --enable-threads --dis
able-win32-registry
Thread model: win32
gcc version 3.3.1 (mingw special 20030804-1)

Upvotes: 2

Views: 794

Answers (1)

paxdiablo
paxdiablo

Reputation: 881303

You probably don't want to try and use *.a files (or the *.o files within them) that were generated under Linux.

Those things have been compiled for the Linux environment and you'll almost certainly find the ABI (application binary interface) is different in CygWin.

CygWin gives you a programming environment similar to Linux, so that you can mostly compile the same code. In that sense, it's compatible at the API (application programming interface) layer, not necessarily the ABI layer.

Upvotes: 3

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