Error executing STRLWR function under Linux: LD returned 1 exit status

Execute strlwr function times wrong. The source program such as the following:

#include <stdio.h> #include <string.h>void main () {char s[10]={"China"}; printf ("%s\n", STRLWR (s)); return 0 ;}

Error content such as the following:

eg6527a.c:in function ' main ':

Eg6527a.c:8:2:warning: ' Return ' with a value, in function returning void [enabled by default] return 0; ^in file included from Eg6527a.c:3:0:eg6527a.c:at top level:/usr/include/strlwr.h:1:14:warning: ' strlwr ' used but never              defined [enabled by default] static char *strlwr (char *s); ^/tmp/cc6lxd8t.o:in function ' main ': eg6527a.c: (. text+0x79): Undefined reference to ' STRLWR ' Collect2:error:ld returned 1 exit status

Look for the reason, originally is the compatibility problem strlwr, STRUPR function is not the standard C function library, only can use in the VC,

These functions need to be customized under Linux gcc.

The detailed procedure is for example the following:

Write yourself a strlwr.h header file, such as the following:

Char *strlwr (char *s) {char *str; str = s; while (*str! = ') {  if (*str >= ' A ' && *str <= ' Z ') {     *s TR + = ' A '-' a '; } str++; } return s; }

Save it under the/usr/include folder

Then change the source file to:

#include <stdio.h> #include <string.h> #include <strlwr.h>void main () {char s[10]={"China"}; printf (" %s\n ", STRLWR (s)); return 0;}

Execute the program again at this time Gcc-o 6527a 6527a.c

To generate a running file 6527a

Execute the file./6527a

The result is: China

Convert the string "China" to: "China"

Error executing STRLWR function under Linux: LD returned 1 exit status