#include <netdb.h> void endprotoent(void); struct protoent *getprotobyname(const char *name); struct protoent *getprotobynumber(int proto); struct protoent *getprotoent(void); void setprotoent(int stayopen);
The setprotoent() function shall open a connection to the database, and set the next entry to the first entry. If the stayopen argument is non-zero, the connection to the network protocol database shall not be closed after each call to getprotoent() (either directly, or indirectly through one of the other getproto*() functions), and the implementation may maintain an open file descriptor for the database.
The getprotobyname() function shall search the database from the beginning and find the first entry for which the protocol name specified by name matches the p_name member, opening and closing a connection to the database as necessary.
The getprotobynumber() function shall search the database from the beginning and find the first entry for which the protocol number specified by proto matches the p_proto member, opening and closing a connection to the database as necessary.
The getprotoent() function shall read the next entry of the database, opening and closing a connection to the database as necessary.
The getprotobyname(), getprotobynumber(), and getprotoent() functions shall each return a pointer to a protoent structure, the members of which shall contain the fields of an entry in the network protocol database.
The endprotoent() function shall close the connection to the database, releasing any open file descriptor.
The application shall not modify the structure to which the return value points, nor any storage areas pointed to by pointers within the structure. The returned pointer, and pointers within the structure, might be invalidated or the structure or the storage areas might be overwritten by a subsequent call to getprotobyname(), getprotobynumber(), or getprotoent(). The returned pointer, and pointers within the structure, might also be invalidated if the calling thread is terminated.
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