在主程序中调用 PQconnectdb 时都运行得很好,但是如果我在函数内部调用它,则会出现段错误。这里是运行的代码
#include <stdio.h>
#include <stdlib.h>
#include <postgresql/libpq-fe.h>
#define PG_HOST "127.0.0.1"
#define PG_USER "postgres"
#define PG_DB "postgres"
#define PG_PASS "postgres"
#define PG_PORT 5432
static void
exit_nicely(PGconn *conn)
{
PQfinish(conn);
exit(1);
}
int main( void )
{
char conninfo[250];
PGconn *conn = NULL;
PGresult *pgres = NULL;
sprintf(conninfo, "user=%s password=%s dbname=%s hostaddr=%s port=%d", PG_USER, PG_PASS, PG_DB, PG_HOST, PG_PORT);
conn = PQconnectdb(conninfo);
if (PQstatus(conn) != CONNECTION_OK)
{
fprintf(stderr, "ERROR: Connection to database failed: %s", PQerrorMessage(conn));
exit_nicely(conn);
}
PQfinish(conn);
return 0;
}
这段代码运行得很好。
但是当我把 PQconnect 放在一个函数中时,程序会产生一个段错误
int connect(char* conninfo, PGconn* conn)
{
conn = PQconnectdb(conninfo);
if (PQstatus(conn) != CONNECTION_OK)
{
fprintf(stderr, "ERROR: Connection to database failed: %s", PQerrorMessage(conn));
exit_nicely(conn);
}
return 1;
}
int main( void )
{
char conninfo[250];
PGconn *conn = NULL;
PGresult *pgres = NULL;
sprintf(conninfo, "user=%s password=%s dbname=%s hostaddr=%s port=%d", PG_USER, PG_PASS, PG_DB, PG_HOST, PG_PORT);
connect(conninfo, conn);
if(!conn)
fprintf(stderr, "conn is null.\n");
PQfinish(conn);
return 0;
}
这里是崩溃堆栈
(gdb) where
#0 __strlen_sse2 () at ../sysdeps/x86_64/multiarch/../strlen.S:32
#1 0x00007ffff7893086 in __GI___strdup (s=0x7 <Address 0x7 out of bounds>) at strdup.c:42
#2 0x00007ffff7bbbd87 in ?? () from /usr/lib/libpq.so.5
#3 0x00007ffff7bbc2a5 in ?? () from /usr/lib/libpq.so.5
#4 0x00007ffff7bbe389 in PQconnectStart () from /usr/lib/libpq.so.5
#5 0x00007ffff7bbe416 in PQconnectdb () from /usr/lib/libpq.so.5
#6 0x0000000000400912 in connect (conninfo=0x7 <Address 0x7 out of bounds>, conn=0x60a630) at pqconnect.c:25
#7 0x00007ffff7bbcadb in PQconnectPoll () from /usr/lib/libpq.so.5
#8 0x00007ffff7bbd77e in ?? () from /usr/lib/libpq.so.5
#9 0x00007ffff7bbe3b4 in PQconnectStart () from /usr/lib/libpq.so.5
#10 0x00007ffff7bbe416 in PQconnectdb () from /usr/lib/libpq.so.5
#11 0x0000000000400912 in connect (conninfo=0x7fffffffe600 "user=btel_user password=JwN5K9e18PsTb dbname=ULIC hostaddr=127.0.0.1 port=5432", conn=0x0) at pqconnect.c:25
#12 0x00000000004009e3 in main () at pqconnect.c:49
当我将函数连接声明为静态时,不会发生段错误错误,但变量 conn 的返回指针为 NULL
为什么?:(