getprotobyname()--Get Protocol Information for Protocol Name
BSD 4.3 Syntax
#include <netdb.h> struct protoent *getprotobyname(char *protocol_name)
Service Program Name: QSOSRV2
Default Public Authority: *USE
Threadsafe: No; see Usage Notes.
UNIX® 98 Compatible Syntax
#define _XOPEN_SOURCE 520 #include <netdb.h> struct protoent *getprotobyname(const char *protocol_name)
Service Program Name: QSOSRV2
Default Public Authority:*USE
Threadsafe: No; see Usage Notes.
The getprotobyname() function is used to retrieve information about a protocol. The information is retrieved from the protocol database file.
There are two versions of the API, as shown above. The base IBM® i API uses BSD 4.3 structures and syntax. The other uses syntax and structures compatible with the UNIX 98 programming interface specifications. You can select the UNIX 98 compatible interface with the _XOPEN_SOURCE macro.
Parameters
- protocol_name
- (Input) The pointer to the character string that contains the name of the protocol for which information is to be retrieved.
Authorities
No authorization is required.
Return Value
getprotobyname() returns a pointer. Possible values are:
- NULL (unsuccessful)
- p (successful), where p is a pointer to struct protoent
The structure struct protoent is defined in <netdb.h>.
struct protoent { char *p_name; char **p_aliases; int p_proto; };
p_name points to the character string that contains the name of the protocol. p_aliases is a pointer to a NULL-terminated array of alternate names for the protocol. p_proto is the protocol number.
Usage Notes
- System i® Navigator or the following CL commands can be
used to access the protocol database file:
- WRKPCLTBLE (Work with Protocol Table Entries)
- ADDPCLTBLE (Add Protocol Table Entry)
- RMVPCLTBLE (Remove Protocol Table Entry)
- WRKPCLTBLE (Work with Protocol Table Entries)
- The pointer returned by getprotobyname() points to static storage
that is overwritten on subsequent calls to the getprotobyname(),
getprotobynumber(), or getprotoent() functions.
- When the protocol information is obtained from the protocol database file,
the file is opened and the protocol information is retrieved (if it exists)
from the file. The file is then closed only if a setprotoent() with a
nonzero parameter value was not previously done.
- A coded character set identifier (CCSID) of 65535 for the job requests that
no database translation be performed. For translation to occur for the protocol
name specified by the protocol_name parameter, and for the protocol
names returned in the protoent structure, the job CCSID must be something other
than 65535.
- Do not use the getprotobyname() function in a multithreaded
environment. See the multithread alternative getprotobyname_r()
function.
- When you develop in C-based languages and an application is compiled with the _XOPEN_SOURCE macro defined to the value 520 or greater, the getprotobyname() API is mapped to qso_getprotobyname98().
Related Information
- _XOPEN_SOURCE--Using _XOPEN_SOURCE for the
UNIX 98 compatible interface
- getprotobynumber()--Get Protocol Information for
Protocol Number
- getprotoent()--Get Next Entry from Protocol
Database
- setprotoent()--Open Protocol Database
- endprotoent()--Close Protocol Database
API introduced: V4R2