On Saturday 24 of April 2010 10:34:08 Daniel Stenberg wrote: > On Sat, 24 Apr 2010, Kamil Dudka wrote: > > You say there we need to "make sure that maxfd is bigger than -1". But > > in the code you intentionally do not in order to keep it working. What > > about updating all the comments like following? > > > > /* In a real-world program you OF COURSE check the return code of the > > function calls. On success, the value of maxfd is guaranteed to be > > greater or equal than than -1. We call select(maxfd + 1, ...), specially > > in case of (maxfd == -1), we call select(0, ...), which is basically > > equal to sleep. */ > > Yes I think that is a good idea. That seems like a better comment to use so > that it is made more obvious what happens in the -1 case.
proposed patch Kamil
From 4e7ddcc756253645b56724db375dc1ab94e44931 Mon Sep 17 00:00:00 2001 From: Kamil Dudka <[email protected]> Date: Sat, 24 Apr 2010 12:05:37 +0200 Subject: [PATCH] test536: do not fail with threaded DNS resolver Also tweaked comments in certain examples using curl_multi_fdset(). --- CHANGES | 4 ++++ docs/examples/fopen.c | 8 +++++--- docs/examples/multi-app.c | 8 +++++--- docs/examples/multi-debugcallback.c | 8 +++++--- docs/examples/multi-double.c | 8 +++++--- docs/examples/multi-post.c | 8 +++++--- docs/examples/multi-single.c | 8 +++++--- tests/libtest/lib536.c | 16 ++++++++++++---- 8 files changed, 46 insertions(+), 22 deletions(-) diff --git a/CHANGES b/CHANGES index 0184671..b765387 100644 --- a/CHANGES +++ b/CHANGES @@ -6,6 +6,10 @@ Changelog +Kamil Dudka (24 Apr 2010) +- Fixed test536 in order to not fail with threaded DNS resolver and tweaked + comments in certain examples using curl_multi_fdset(). + Daniel Stenberg (21 Apr 2010) - The -O option caused curl to crash on windows and DOS due to the tool writing out of boundary memory. diff --git a/docs/examples/fopen.c b/docs/examples/fopen.c index e3814e6..ec12bd0 100644 --- a/docs/examples/fopen.c +++ b/docs/examples/fopen.c @@ -131,7 +131,6 @@ fill_buffer(URL_FILE *file,int want,int waittime) fd_set fdread; fd_set fdwrite; fd_set fdexcep; - int maxfd; struct timeval timeout; int rc; @@ -144,6 +143,7 @@ fill_buffer(URL_FILE *file,int want,int waittime) /* attempt to fill buffer */ do { + int maxfd = -1; FD_ZERO(&fdread); FD_ZERO(&fdwrite); FD_ZERO(&fdexcep); @@ -156,8 +156,10 @@ fill_buffer(URL_FILE *file,int want,int waittime) curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd); /* In a real-world program you OF COURSE check the return code of the - function calls, *and* you make sure that maxfd is bigger than -1 - so that the call to select() below makes sense! */ + function calls. On success, the value of maxfd is guaranteed to be + greater or equal than than -1. We call select(maxfd + 1, ...), + specially in case of (maxfd == -1), we call select(0, ...), which is + basically equal to sleep. */ rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout); diff --git a/docs/examples/multi-app.c b/docs/examples/multi-app.c index a86dd0e..699ce59 100644 --- a/docs/examples/multi-app.c +++ b/docs/examples/multi-app.c @@ -66,7 +66,7 @@ int main(int argc, char **argv) fd_set fdread; fd_set fdwrite; fd_set fdexcep; - int maxfd; + int maxfd = -1; FD_ZERO(&fdread); FD_ZERO(&fdwrite); @@ -80,8 +80,10 @@ int main(int argc, char **argv) curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd); /* In a real-world program you OF COURSE check the return code of the - function calls, *and* you make sure that maxfd is bigger than -1 so - that the call to select() below makes sense! */ + function calls. On success, the value of maxfd is guaranteed to be + greater or equal than than -1. We call select(maxfd + 1, ...), + specially in case of (maxfd == -1), we call select(0, ...), which is + basically equal to sleep. */ rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout); diff --git a/docs/examples/multi-debugcallback.c b/docs/examples/multi-debugcallback.c index b10b47c..96af1c4 100644 --- a/docs/examples/multi-debugcallback.c +++ b/docs/examples/multi-debugcallback.c @@ -140,7 +140,7 @@ int main(int argc, char **argv) fd_set fdread; fd_set fdwrite; fd_set fdexcep; - int maxfd; + int maxfd = -1; FD_ZERO(&fdread); FD_ZERO(&fdwrite); @@ -154,8 +154,10 @@ int main(int argc, char **argv) curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd); /* In a real-world program you OF COURSE check the return code of the - function calls, *and* you make sure that maxfd is bigger than -1 - so that the call to select() below makes sense! */ + function calls. On success, the value of maxfd is guaranteed to be + greater or equal than than -1. We call select(maxfd + 1, ...), + specially in case of (maxfd == -1), we call select(0, ...), which is + basically equal to sleep. */ rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout); diff --git a/docs/examples/multi-double.c b/docs/examples/multi-double.c index ef3bf92..66ae737 100644 --- a/docs/examples/multi-double.c +++ b/docs/examples/multi-double.c @@ -57,7 +57,7 @@ int main(int argc, char **argv) fd_set fdread; fd_set fdwrite; fd_set fdexcep; - int maxfd; + int maxfd = -1; FD_ZERO(&fdread); FD_ZERO(&fdwrite); @@ -71,8 +71,10 @@ int main(int argc, char **argv) curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd); /* In a real-world program you OF COURSE check the return code of the - function calls, *and* you make sure that maxfd is bigger than -1 so - that the call to select() below makes sense! */ + function calls. On success, the value of maxfd is guaranteed to be + greater or equal than than -1. We call select(maxfd + 1, ...), + specially in case of (maxfd == -1), we call select(0, ...), which is + basically equal to sleep. */ rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout); diff --git a/docs/examples/multi-post.c b/docs/examples/multi-post.c index 229e843..e01693e 100644 --- a/docs/examples/multi-post.c +++ b/docs/examples/multi-post.c @@ -77,7 +77,7 @@ int main(int argc, char *argv[]) fd_set fdread; fd_set fdwrite; fd_set fdexcep; - int maxfd; + int maxfd = -1; FD_ZERO(&fdread); FD_ZERO(&fdwrite); @@ -91,8 +91,10 @@ int main(int argc, char *argv[]) curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd); /* In a real-world program you OF COURSE check the return code of the - function calls, *and* you make sure that maxfd is bigger than -1 - so that the call to select() below makes sense! */ + function calls. On success, the value of maxfd is guaranteed to be + greater or equal than than -1. We call select(maxfd + 1, ...), + specially in case of (maxfd == -1), we call select(0, ...), which is + basically equal to sleep. */ rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout); diff --git a/docs/examples/multi-single.c b/docs/examples/multi-single.c index 3e236f3..cc3b6c8 100644 --- a/docs/examples/multi-single.c +++ b/docs/examples/multi-single.c @@ -51,7 +51,7 @@ int main(int argc, char **argv) fd_set fdread; fd_set fdwrite; fd_set fdexcep; - int maxfd; + int maxfd = -1; FD_ZERO(&fdread); FD_ZERO(&fdwrite); @@ -65,8 +65,10 @@ int main(int argc, char **argv) curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd); /* In a real-world program you OF COURSE check the return code of the - function calls, *and* you make sure that maxfd is bigger than -1 so - that the call to select() below makes sense! */ + function calls. On success, the value of maxfd is guaranteed to be + greater or equal than than -1. We call select(maxfd + 1, ...), + specially in case of (maxfd == -1), we call select(0, ...), which is + basically equal to sleep. */ rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout); diff --git a/tests/libtest/lib536.c b/tests/libtest/lib536.c index 04bc696..158b3a1 100644 --- a/tests/libtest/lib536.c +++ b/tests/libtest/lib536.c @@ -21,7 +21,7 @@ static CURLMcode perform(CURLM * multi) { - int handles, maxfd; + int handles; CURLMcode code; fd_set fdread, fdwrite, fdexcep; struct timeval mp_start; @@ -31,6 +31,9 @@ static CURLMcode perform(CURLM * multi) mp_start = tutil_tvnow(); for (;;) { + static struct timeval timeout = /* 100 ms */ { 0, 100000L }; + int maxfd = -1; + code = curl_multi_perform(multi, &handles); if (tutil_tvdiff(tutil_tvnow(), mp_start) > MULTI_PERFORM_HANG_TIMEOUT) { @@ -53,9 +56,14 @@ static CURLMcode perform(CURLM * multi) FD_ZERO(&fdwrite); FD_ZERO(&fdexcep); curl_multi_fdset(multi, &fdread, &fdwrite, &fdexcep, &maxfd); - if (maxfd < 0) - return (CURLMcode) ~CURLM_OK; - if (select(maxfd + 1, &fdread, &fdwrite, &fdexcep, 0) == -1) + + /* In a real-world program you OF COURSE check the return code of the + function calls. On success, the value of maxfd is guaranteed to be + greater or equal than than -1. We call select(maxfd + 1, ...), + specially in case of (maxfd == -1), we call select(0, ...), which is + basically equal to sleep. */ + + if (select(maxfd + 1, &fdread, &fdwrite, &fdexcep, &timeout) == -1) return (CURLMcode) ~CURLM_OK; } -- 1.7.0.2
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