#include <semaphore.h> #include <qlg.h> sem_t * QlgSem_open_np(const Qlg_Path_Name_T *name, int oflag mode_t mode, unsigned int value, sem_attr_np_t * attr);
The QlgSem_open_np() function, like the sem_open_np() function, opens a named semaphore and returns a semaphore pointer that may be used on subsequent calls to sem_post(), sem_post_np(), sem_wait(), sem_wait_np(), sem_trywait(), sem_getvalue(), and sem_close(). The QlgSem_open_np() function takes a pointer to a Qlg_Path_Name_T structure, while the sem_open_np() function takes a pointer to a character string.
Limited information on the name parameter is provided in this API. For additional information on the name parameter and a discussion of other parameters, authorities required, return values, and related information, see sem_open_np()--Open Named Semaphore with Maximum Value.
If QlgSem_open_np() is not successful, errno usually indicates the following error or one of the errors identified in sem_open_np()--Open Named Semaphore with Maximum Value.
Note: All of the related information for sem_open_np() applies to QlgSem_open_np(). See Related Information in sem_open().
See Code disclaimer information for information pertaining to code examples.
The following example opens the named semaphore "/mysemaphore" and creates the semaphore with an initial value of 10 and a maxiumum value of 11. The permissions are set such that only the current user has access to the semaphore.
#include <semaphore.h> #include <qlg.h> main() { sem_t * my_semaphore; int rc; sem_attr_np_t attr; #define mypath "/mysemaphore" const char US_const[3]= "US"; const char Language_const[4]="ENU"; const char Path_Name_Del_const[2]= "/"; typedef struct pnstruct { Qlg_Path_Name_T qlg_struct; char[100] pn; /* This size must be >= the path */ /* name length or be a pointer */ /* to the path name. */ }; struct pnstruct path; /***************************************************************/ /* Initialize Qlg_Path_Name_T parameters */ /***************************************************************/ memset((void*)path name, 0x00, sizeof(struct pnstruct)); path.qlg_struct.CCSID = 37; memcpy(path.qlg_struct.Country_ID,US_const,2); memcpy(path.qlg_struct.Language_ID,Language_const,3); path.qlg_struct.Path_Type = QLG_CHAR_SINGLE; path.qlg_struct.Path_Length = sizeof(mypath)-1; memcpy(path.qlg_struct.Path_Name_Delimiter,Path_Name_Del_const,1); memcpy(path.pn,mypath,sizeof(mypath)); memset(&attr, 0, sizeof(attr)); attr.maxvalue=11; my_semaphore = QlgSem_open_np((Qlg_Path_Name_T *)path name, O_CREAT|O_EXCL, S_IRUSR | S_IWUSR, 10, &attr); }
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