DCMD_PROC_SETALTREG

Set the alternate register set with the values provided for the process associated with the file descriptor.

#include <sys/procfs.h>

#define DCMD_PROC_SETALTREG   __DIOT(_DCMD_PROC, __PROC_SUBCMD_PROCFS + 22, procfs_fpreg)

The arguments to devctl() are:

Argument Value
filedes A file descriptor for the process.
dcmd DCMD_PROC_SETALTREG
dev_data_ptr A pointer to a procfs_fpreg structure
n_bytes sizeof(procfs_fpreg)
dev_info_ptr NULL

You must have opened the file descriptor for writing. The argument is a pointer to a procfs_fpreg structure (see debug_fpreg_t in <sys/debug.h>) that specifies to set the values of the alternate register set. For example:

procfs_fpreg reg;

/* Set the members of reg as required. */
devctl( fd, DCMD_PROC_SETALTREG, &reg, sizeof(reg), NULL);

To get the alternate register set, use DCMD_PROC_GETALTREG.