strncpy + strlen is pointless #312
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strlen already assumes that the string is NULL-terminated. Fixes -Wstringop-overflow warning
orestisfl
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Oct 3, 2018
strlen already assumes that the string is NULL-terminated. Like in i3/i3status#312 but for whatever reason gcc didn't warn about this here.
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I've just come across a similar occurrence (but with strncmp) in i3status.h: #define BEGINS_WITH(haystack, needle) (strncmp(haystack, needle, strlen(needle)) == 0) Does this fall into the same category? |
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No, that's correct. Example: char *a = "Hello World!";
char *b = "Hello";
printf("%d %d\n", strcmp(a, b), strncmp(a, b, strlen(b))); |
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Ah - yes. I was actually experimenting with: bool begins_with(const char *haystack, const char *needle) { which works, I think. |
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Yes, this works. But we wouldn't want to replace something using standard string comparison functions with our own implementation. It's not easier to understand and it's not faster either: the glibc implementation uses SSE optimizations and the strlen call should be replaced by the compiler. |
stapelberg
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Oct 7, 2018
stapelberg
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Oct 7, 2018
strlen already assumes that the string is NULL-terminated. Like in i3/i3status#312 but for whatever reason gcc didn't warn about this here.
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