TipcMsgAppendStrPtr

Name

TipcMsgAppendStrPtr — use a pointer to append a STR field to a message

Synopsis

T_BOOL TipcMsgAppendStrPtr(msg, str_data, field_return) 
T_IPC_MSG msg; 
T_STR str_data; 
T_IPC_MSG_FIELD *field_return; 

Arguments

msg — message to append field to

str_data — data for new message field

field_return — optional location to return field (use NULL if not needed)

Return Values

TRUE if the field was successfully appended to the message, FALSE otherwise.

Diagnostics

If TipcMsgAppendStrPtr fails, it returns FALSE and sets the global SmartSockets error number to one of:

Description

TipcMsgAppendStrPtr appends a null-terminated character STR field containing str_data to the end of a message’s data. This function does not make a copy of the string. Instead, the supplied pointer to the string is entered directly into the new message field’s internal data structure. The caller is responsible for making sure that the pointer remains valid for the lifetime of the message field, and for freeing it, if necessary, when the message field has been destroyed.

One advantage of TipcMsgAppendStrPtr over TipcMsgAppendStr is that the string can be modified after the field is appended, but before the message is sent. Also, the overhead of one copy operation is avoided, because the character string is still copied into the connection message buffer when the message is sent.

To update the pointer to point to a new memory location, use the TipcMsgFieldUpdateStrPtr function.

Caution

None

See Also

TipcMsgAppendStr, TipcMsgNextStr, TipcMsgFieldSetSize, TipcMsgFieldUpdateStrPtr

Examples

This example creates a message and appends a pointer to a STR field:

T_IPC_MT mt; 
T_IPC_MSG msg; 
T_CHAR str[80]; 
T_IPC_MSG_FIELD field; 
 
#define USER_MT_STR_TEST 100 
mt = TipcMtCreate("str_test", USER_MT_STR_TEST, "str"); 
if (mt == NULL) { 
  return;  /* error */ 
} 
 
msg = TipcMsgCreate(mt); 
if (mt == NULL) { 
  return;  /* error */ 
} 
 
/* An RTclient would typically set the destination of */ 
/* a message at this point by calling TipcMsgSetDest. */ 
 
str[0] = '\0'; 
if (!TipcMsgAppendStrPtr(msg, str, &field)) { 
  return;  /* error */ 
}  
 
strcpy(str, "This is the field data."); 
if (!TipcMsgFieldSetSize(field, strlen(str) + 1)) { 
  return;  /* error */ 
} 
 
/* A process would typically send a message at this point by */ 
/* calling TipcConnMsgSend or TipcSrvMsgSend. */ 
 
/* A process would typically destroy a message at this point by */ 
/* calling TipcMsgDestroy. */