我运行测试后的结论是这样的：确实发生了内存泄漏。没有回收sqlca区域。
因为，我修改了 /src/interfaces/ecpg/ecpglib/misc.c的代码后，
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#ifdef ENABLE_THREAD_SAFETY
static void
ecpg_sqlca_key_destructor(void *arg)
{
FILE *p1;
p1=fopen("gaoecpg.1","w+");
fclose(p1);
free(arg); /* sqlca structure allocated in ECPGget_sqlca */
FILE *p2;
p2=fopen("gaoecpg.2","w+");
fclose(p2);
}
static void
ecpg_sqlca_key_init(void)
{
FILE *p3;
p3=fopen("gaoecpg.3","w+");
fclose(p3);
pthread_key_create(&sqlca_key, ecpg_sqlca_key_destructor);
FILE *p6;
p6=fopen("gaoecpg.6","w+");
fclose(p6);
}
#endif
struct sqlca_t *
ECPGget_sqlca(void)
{
#ifdef ENABLE_THREAD_SAFETY
FILE *p4;
p4=fopen("gaoecpg.4","w+");
fclose(p4);
struct sqlca_t *sqlca;
pthread_once(&sqlca_key_once, ecpg_sqlca_key_init);
sqlca = pthread_getspecific(sqlca_key);
if (sqlca == NULL)
{
sqlca = malloc(sizeof(struct sqlca_t));
ecpg_init_sqlca(sqlca);
pthread_setspecific(sqlca_key, sqlca);
}
return (sqlca);
#else
FILE *p5;
p5=fopen("gaoecpg.5","w+");
fclose(p5);
return (&sqlca);
#endif
}
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无论连接是成功还是失败，都生成三个文件：
gaoecpg.3,gaoecpg.4, gaoecpg.6
下面是我的测试程序 ：
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#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int cm_connectdb(const char *DbUid,const char *DbPswd,const char *Hostname,char *pcSqlErrm)
{
EXEC SQL BEGIN DECLARE SECTION;
varchar sUserid[20];
varchar sPasswd[20];
varchar sHostname[64];
EXEC SQL END DECLARE SECTION;
memset(sUserid.arr, '\0',sizeof(sUserid.arr));
memset(sPasswd.arr, '\0',sizeof(sPasswd.arr));
memset(sHostname.arr, '\0',sizeof(sHostname.arr));
if (DbUid == NULL || DbPswd == NULL ||
Hostname == NULL || pcSqlErrm == NULL){
return -1;
}
strcpy((char *)sUserid.arr, DbUid);
sUserid.len = (unsigned short)strlen((char *)sUserid.arr);
strcpy((char *)sPasswd.arr, DbPswd);
sPasswd.len = (unsigned short)strlen((char *)sPasswd.arr);
strcpy((char *)sHostname.arr, Hostname);
sHostname.len = (unsigned short)strlen((char *)sHostname.arr);
EXEC SQL CONNECT TO :sHostname AS CM_DBCONN USER:sUserid IDENTIFIED BY :sPasswd;
if (sqlca.sqlcode!=0){
fprintf(stderr,"Connection Failed.\n");
EXEC SQL DISCONNECT CM_DBCONN;
return -1;
}else{
fprintf(stderr,"Connection Succeeded!\n");
}
EXEC SQL DISCONNECT CM_DBCONN;
return 0;
}
int main(){
int ist=0;
char * perr;
perr = (char *) malloc (sizeof(char)*64);
const char * pusr="postgres";
const char * ppass="postgres";
const char * phost="postgres@localhost:5432";
ist= cm_connectdb(pusr,ppass,phost,perr);
free(perr);
return 0;
}
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虽然，按照网上的说法，理论上：线程结束的时候，就会自动调用pthread_key_create注册的函数
但是至少我遇到的情况，并非如此。
本文转自健哥的数据花园博客园博客，原文链接：http://www.cnblogs.com/gaojian/archive/2012/08/22/2650781.html，如需转载请自行联系原作者
