Messages in this thread | | | Date | Tue, 1 Jan 2019 19:00:51 +0100 | From | Jiri Olsa <> | Subject | Re: perf: Use strcmp(str, "const") instead of strncmp(str, "const", sizeof("const")) |
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On Thu, Dec 20, 2018 at 03:55:53PM -0300, Arnaldo Carvalho de Melo wrote: > Em Thu, Dec 20, 2018 at 12:26:01PM -0500, Steven Rostedt escreveu: > > As strncmp(str, "const", sizeof("const") is exactly the same as > > strcmp(str, "const") use that instead, otherwise it is confusing. > > > > sizeof("const") includes the nul terminator ('\0') of the string > > "const", and that means strncmp() will only return a match if str and > > "const" are exactly the same, which is what strcmp() does. > > There are more of those, that are there from time immemorial, lemme see > if the original intention can be found... > > commit 26d330226b9cf6208daae9b0b3697980c8fb51d8 > Author: Jiri Olsa <jolsa@redhat.com> > Date: Tue Aug 7 15:20:47 2012 +0200 > > perf tools: Support for DWARF mode callchain > > ---------------- > > I thought this could be because at the time strchr was used and thus the > name would be in a buffer followed by ',' or other separator, but > strtok_r() was used, so your patch should simplify things.
yea, strtok_r returns null-terminated string containing the next token, so there's always trailing null terminator.. so those strncmp calls work properly
jirka
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