C Error: undefined reference to '_itoa'

c itoa
aytee17 picture aytee17 · Mar 25, 2011 · Viewed 52.5k times · Source

I'm trying to convert an integer to a character to write to a file, using this line:

fputc(itoa(size, tempBuffer, 10), saveFile);

and I receive this warning and message:

warning: implicit declaration of 'itoa'

undefined reference to '_itoa'

I've already included stdlib.h, and am compiling with:

gcc -Wall -pedantic -ansi

Any help would be appreciated, thank you.

Answer

Brian Roach picture Brian Roach · Mar 25, 2011

itoa is not part of the standard. I suspect either -ansi is preventing you from using it, or it's not available at all.

I would suggest using sprintf()

If you go with the c99 standard, you can use snprintf() which is of course safer.

char buffer[12];
int i = 20;
snprintf(buffer, 12,"%d",i);

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