undefined reference to `strlwr'
c, linker-errors, string
Solution
`strlwr()` is not standard C function. Probably it's provided by one implementation while the other compiler you use don't.
You can easily implement it yourself:
#include <string.h>
#include<ctype.h>
char *strlwr(char *str)
{
unsigned char *p = (unsigned char *)str;
while (*p) {
*p = tolower((unsigned char)*p);
p++;
}
return str;
}
Problem
My code is like a text compressor, reading normal text and turns into numbers, every word has a number. It compiles in DevC++ but does not end, however, it does not compile in Ubuntu 13.10. I'm getting an error like in the title in Ubuntu "undefined reference to `strlwr'", my code is a little long so I am not able to post it here, but one of the error is from here: ``` //operatinal funcitons here int main() { int i = 0, select; char filename[50], textword[40], find[20], insert[20], delete[20]; FILE *fp, *fp2, *fp3; printf("Enter the file name: "); fflush(stdout); scanf("%s", filename); fp = fopen(filename, "r"); fp2 = fopen("text.txt", "w+"); while (fp == NULL) { printf("Wrong file name, please enter file name again: "); fflush(stdout); scanf("%s", filename); fp = fopen(filename, "r"); } while (!feof(fp)) { while(fscanf(fp, "%s", textword) == 1) { strlwr(textword); //some other logic } } .... //main continues ```