{"id":527,"date":"2013-12-27T23:39:00","date_gmt":"2013-12-27T15:39:00","guid":{"rendered":"http:\/\/note.systw.net\/note\/?p=527"},"modified":"2023-11-03T23:44:40","modified_gmt":"2023-11-03T15:44:40","slug":"c%e8%aa%9e%e8%a8%80-linux-thread","status":"publish","type":"post","link":"https:\/\/systw.net\/note\/archives\/527","title":{"rendered":"C\u8a9e\u8a00-Linux thread"},"content":{"rendered":"\n

pthread<\/strong>
POSIX thread\u70baPOSIX\u6a19\u6e96\u57f7\u884c\u7dd2.\u5b9a\u7fa9thread\u7684\u5efa\u7acb\u53ca\u4f7f\u7528\u65b9\u6cd5
pthread.h\u4e2d\u5e38\u7528\u7684\u6709:
pthread_create\u3001pthread_dispath\u3001pthread_mutex_lock(\u4e92\u65a5\u9396\u5b9a)\u3001pthread_mutex_unlock(\u4e92\u65a5\u89e3\u9396)
\u6240\u6709pthread.h\u53ef\u7528\u7684function\u53ef\u53c3\u8003 POSIX thread (pthread) libraries
http:\/\/www.yolinux.com\/TUTORIALS\/LinuxTutorialPosixThreads.html<\/p>\n\n\n\n

ps
\u82e5\u5728linux\u4e0bgcc\u7de8\u8b6f\uff0c\u9700\u52a0-lpthread\u53c3\u6578
ex:
gcc thread.c -o thread -lpthread<\/p>\n\n\n\n

……………………………………………..<\/p>\n\n\n\n

\u5e38\u898b\u51fd\u6578\u8aaa\u660e<\/p>\n\n\n\n

pthread_create()<\/h2>\n\n\n\n

\u5efa\u7acbthread
\u51fd\u6578\u539f\u5f62\u5982\u4e0b
int pthread_create(pthread_t *thread, const pthread_attr_t *attr, void *(*start_routine) (void *), void *arg);<\/strong>
\u53c3\u6578\u8aaa\u660e\u5982\u4e0b
pthread_t<\/strong>\u00a0*thread\uff1a thread id
const pthread_attr_t *restrict attr<\/strong>\uff1athread\u5c6c\u6027
void *(*start_routine) (void *)<\/strong>\uff1a\u6307\u5b9a\u8981\u505a\u70bathread\u7684function
void *arg<\/strong>\uff1a\u7d66thread\u7684\u53c3\u6578
ps:
thread\u5efa\u7acb\u6210\u529f\u5f8c\uff0c\u51fd\u6578\u6703\u50b3\u56de0
\u82e5\u5efa\u7acb\u5931\u6557\u5247\u56de\u50b3\u932f\u8aa4\u4ee3\u78bc\uff0c\u5e38\u898b\u4ee3\u78bc\u70baEAGAIN\u548cEINVAL
EAGAIN\u8868\u793a\u5efa\u7acb\u7684thread\u6578\u91cf\u5df2\u8d85\u904e\u7cfb\u7d71\u9650\u5236\u7684thread\u6578\u91cf
EINVAL\u8868\u793athread\u5c6c\u6027\u4e0d\u6b63\u78ba<\/p>\n\n\n\n

ex:
void printmsg(void);
.... omit ...
pthread_t tid;
pthread_create(&tid, NULL, (void *) printmsg, NULL);
.... omit ...
ex
void *printmsg_a(void *arg);
void *printmsg_b(void *arg);
.... omit ...
pthread_t tid1, tid2;
pthread_create(&tid1, NULL, &printmsg_a, NULL);
pthread_create(&tid2, NULL, &printmsg_b, NULL);
.... omit ...
ex
void *printmsg(void *arg); \/\/argv[1]\u4ee3\u5165arg
.... omit ...
pthread_t tid;
pthread_attr_t attr;
pthread_attr_init(&attr);
char *argv[];
pthread_create(&tid, &attr, printmsg, argv[1]);
.... omit ...
ex:
void *printmsg( void *arg ){.... \/\/message\u4ee3\u5165arg
.... omit ...
pthread_t tid1, tid2;
const char *message1 = \"thread1\";
const char *message2 = \"thread2\";
iret1 = pthread_create( &tid1, NULL, printmsg, (void*) message1);
iret2 = pthread_create( &tid2, NULL, printmsg, (void*) message2);
.... omit ...<\/code><\/pre>\n\n\n\n

pthread_join()<\/h2>\n\n\n\n
\u7b49\u5f85\u6307\u5b9a\u7684thread\u7d50\u675f
\u51fd\u6578\u539f\u578b\u5982\u4e0b
int pthread_join(pthread_t thread, void **thread_return);<\/strong>
\u53c3\u6578\u8aaa\u660e\u5982\u4e0b
pthread_t thread<\/strong>: thread id
void **thread_return<\/strong>: \u7528\u4f86\u5132\u5b58thread\u7684\u56de\u50b3\u503c
ps:
\u7576\u7b49\u5f85\u6307\u5b9a\u7684thread\u7d50\u675f\u6642,\u8a72\u51fd\u6578\u6703\u88ab\u6536\u56de
ex:
pthread_join(id,NULL);<\/p>\n\n\n\n
pthread_exit()<\/h2>\n\n\n\n
thread\u81ea\u5df1\u7d50\u675f
\u51fd\u6578\u539f\u578b\u5982\u4e0b
void pthread_exit(void *retval);<\/strong>
ex:
pthread_exit(0);<\/p>\n\n\n\n
pthread_key_create<\/h2>\n\n\n\n
\u5efa\u7acbthread\u5168\u57df\u8b8a\u6578<\/p>\n\n\n\n
ex
#define NUMTHREADS 3
pthread_key_t glob_var_key;
pthread_t threads[NUMTHREADS];
int i;
pthread_key_create(&glob_var_key,NULL);
for (i=0; i < NUMTHREADS; i++){
pthread_create(&threads[i],NULL,thread_func,NULL);
}
for (i=0; i < NUMTHREADS; i++){
pthread_join(threads[i], NULL);
}
...omit...
void* thread_func(void *arg){
pthread_setspecific(glob_var_key, &glob_var);
...omit...<\/code><\/pre>\n\n\n\n

……………………………………………………………………….<\/p>\n\n\n\n
\u5e38\u898b\u7bc4\u4f8b<\/p>\n\n\n\n
\u986f\u793a\u8cc7\u8a0a
ray@localhost# vi thread.c<\/strong><\/p>\n\n\n\n
#include
#include
void thread(void){
\u3000int i;
\u3000for(i=0;i<2;i++)printf(\"This is a thread n\");
}
int main(void){
\u3000pthread_t id;
\u3000int i,ret;
\u3000pthread_create(&id,NULL,(void *) thread,NULL);
\u3000for(i=0;i<2;i++)printf(\"This is the process n\");
\u3000pthread_join(id,NULL);
\u3000return (0);
}<\/code><\/pre>\n\n\n\n
ray@localhost# gcc thread.c -o thread -lpthread
ray@localhost# .\/thread<\/strong>
This is the process
This is the process
This is a thread
This is a thread
ps
\u6bcf\u6b21\u7d50\u679c\u4e0d\u4e00\u6a23\uff0c\u9019\u662fthread\u548cmain process\u722d\u596aCPU\u8cc7\u6e90\u7684\u7d50\u679c<\/p>\n\n\n\n

\u8b80\u53d6\u5916\u90e8\u53c3\u6578\u505a\u8a08\u7b97
ray@localhost# vi sum_by_thread.c<\/strong>\u3000<\/p>\n\n\n\n
#include\n#include\nint sum;\nvoid *runner(void *param);\nint main(int argc, char *argv[]){\n\u3000pthread_t tid;\n\u3000pthread_attr_t attr;\n\u3000pthread_attr_init(&attr);\n\u3000pthread_create(&tid,&attr,runner,argv[1]);\n\u3000pthread_join(tid,NULL);\n\u3000printf(\"sum=%dn\",sum);\n}\nvoid *runner(void *param){\n\u3000int i, upper= atoi(param);\n\u3000sum=0;\n\u3000if(upper>0){\n\u3000\u3000for(i=1,i<=upper;i++)sum+=i;\n\u3000}\n\u3000pthread_exit(0);\n}<\/code><\/pre>\n\n\n\n
ray@localhost# gcc sum_by_thread.c -o sum_by_thread -lpthread
ray@localhost# .\/sum_by_thread 3<\/strong>
6<\/p>\n\n\n\n

\u5efa\u7acb\u4e09\u500bthread\u8b80\u53d6\u4e09\u500b\u6a94\u6848
ray@localhost# vi wordthread.c<\/strong><\/p>\n\n\n\n
#include
#include
#include
#define MAX_WLEN 20 \/\/max length of a word
#define MAX_FLEN 6000 \/\/max word in a FILE
#define NUMTID 3 \/\/number of thread
\/\/\/\/\/\/\/\/\/\/\/thread
char wordall[3][MAX_FLEN];
void rfile(char ta[2][20]);
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
int main(int argc, char *argv[]){
\u3000int i;
\u3000\/\/\/\/\/\/\/\/\/\/\/\/\/ read file by thread
\u3000pthread_t tid[NUMTID];
\u3000char tarray[NUMTID][2][20];
\u3000char buffer[1];
\u3000for(i=0;i< NUMTID;i++){
\u3000\u3000sprintf(buffer, \"%d\", i);
\u3000\u3000strcpy(tarray[i][0],buffer); \/\/save thread id
\u3000\u3000strcpy(tarray[i][1],argv[i+1]); \/\/save file path
\u3000\u3000pthread_create(&tid[i], NULL,(void *) rfile,tarray[i]);
\u3000\u3000buffer[0]=' 0 '; \/\/clear array
\u3000}
\u3000for(i=0;i< NUMTID;i++){
\u3000\u3000pthread_join(tid[i],NULL);
\u3000}
\u3000\/\/\/\/\/\/\/\/\/\/\/ collect word from all file
\u3000char word[MAX_WLEN];
\u3000char *token;
\u3000char c;
\u3000int totalword=0;
\u3000for(i=0;i< NUMTID;i++){
\u3000\u3000token = strtok(wordall[i], \" ,.n\");
\u3000\u3000while(token){
\u3000\u3000\u3000strcpy(word, token);
\u3000\u3000\u3000for(c=0;c\u3000\u3000\u3000printf(\"%s n\", word);
\u3000\u3000\u3000totalword++;
\u3000\u3000\u3000token = strtok(NULL, \" ,.n\");
\u3000\u3000}
\u3000printf(\"total word is %d\", totalword);
\u3000}
}
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
\/\/\/\/\/\/\/\/\/\/\/read file in thread
void rfile(char ta[2][20]){
\u3000FILE *aptr;
\u3000char line[MAX_FLEN];
\u3000aptr = fopen(ta[1],\"r\");
\u3000while(!feof(aptr)){
\u3000\u3000fgets(line, MAX_FLEN, aptr);
\u3000\u3000if(feof(aptr)) break;
\u3000\u3000strcpy(wordall[atoi(ta[0])], line);
\u3000}
\u3000fclose(aptr);
\u3000pthread_exit(0);
\u3000}
}<\/code><\/pre>\n\n\n\n
ray@localhost# gcc wordthread.c -o wordthread -lpthread<\/strong>
ray@localhost# .\/wordthread text1 text2 text3<\/strong>
system
linux
is
…omit..
total word is 9<\/p>\n\n\n\n

…………………………………………………<\/p>\n\n\n\n
refer<\/strong>
linux man-page http:\/\/man7.org\/linux\/man-pages\/man3\/
create a global variable http:\/\/stackoverflow.com\/questions\/15100824\/how-do-i-create-a-global-variable-that-is-thread-specific-in-c-using-posix-threa
Linux C\/C++\u591a\u7ebf\u7a0bpthread\u5b9e\u4f8b http:\/\/www.metsky.com\/archives\/550.html
Linux\u4e0b\u7684\u591a\u7dda\u7a0b\u7de8\u7a0b http:\/\/fanqiang.chinaunix.net\/a4\/b8\/20010811\/0905001105_b.html
\u53f0\u7063wiki pthread http:\/\/www.twwiki.com\/wiki\/Pthread<\/p>\n","protected":false},"excerpt":{"rendered":"
pthreadPOSIX thread\u70baPOSIX\u6a19\u6e96\u57f7\u884c\u7dd2 …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"fifu_image_url":"","fifu_image_alt":"","_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[14],"tags":[],"class_list":["post-527","post","type-post","status-publish","format-standard","hentry","category-develop"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/posts\/527","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/comments?post=527"}],"version-history":[{"count":0,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/posts\/527\/revisions"}],"wp:attachment":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/media?parent=527"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/categories?post=527"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/tags?post=527"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}