int boinc_init();
before calling other BOINC functions or doing I/O.
When the application has completed it must call
int boinc_finish(int status);
status is nonzero if an error was encountered.
This call does not return.
int boinc_resolve_filename(char *logical_name, char *physical_name);
to convert logical file names to physical names.
For example, instead of
f = fopen(\"my_file\", \"r\");
the application might use
char resolved_name[256];
retval = boinc_resolve_filename(\"my_file\", resolved_name);
if (retval) fail(\"can't resolve filename\");
f = fopen(resolved_name, \"r\");
boinc_resolve_filename() doesn't need to be used for temporary files.
Frequency of checkpointing is a user preference (e.g. laptop users might want to checkpoint infrequently). An application must call
bool boinc_time_to_checkpoint();
whenever it reaches a point where it is able to checkpoint.
If this returns true,
the application should write the state file and flush all output files,
then call
void boinc_checkpoint_completed();
boinc_time_to_checkpoint() is fast
(it usually makes no system calls),
so can be called frequently (hundreds or thousands of times a second).
boinc_time_to_checkpoint() performs other time-based functions; e.g. it periodically measures the application's CPU time and reports it to the core client. So, even for applications that don't do checkpointing, it should be called at least once a second.
To facilitate atomic checkpoint, an application can write to output and state files using the MFILE class.
class MFILE {
public:
int open(char* path, char* mode);
int _putchar(char);
int puts(char*);
int printf(char* format, ...);
size_t write(const void* buf, size_t size, size_t nitems);
int close();
int flush();
};
MFILE buffers data in memory
and writes to disk only on flush() or close().
This lets you write output files and state files more or less atomically.
The core client GUI displays the percent done of workunits in progress. To keep this display current, an application should periodically call
boinc_fraction_done(double fraction_done);The fraction_done argument is a rough estimate of the workunit fraction complete (0 to 1). This function is fast and can be called frequently.
The following functions get information from the core client; this information may be useful for graphics.
int boinc_get_init_data(APP_INIT_DATA&);
struct APP_INIT_DATA {
char project_preferences[4096];
char user_name[256];
char team_name[256];
double user_total_credit;
double user_expavg_credit;
double team_total_credit;
double team_expavg_credit;
};
to get the following information:
";
list_start();
list_item("project_preferences", "An XML string containing
the user's project-specific preferences.");
list_item("user_name", " the user's 'screen name' on this project.");
list_item("team_name", " the user's team name, if any.");
list_item("user_total_credit", " user's total work for this project.");
list_item("user_expavg_credit", " user's recent average work per day.");
list_item("team_total_credit", " team's total work for this project.");
list_item("team_expavg_credit", " team's recent average work per day.");
list_end();
echo "
An application may call
int boinc_cpu_time(double &cpu_time, double& working_set_size);
to get its total CPU time
(i.e., from the beginning of the work unit,
not just since the last restart).
This also returns the virtual memory working set size in bytes.
Each program should have its own state file; the state file of the coordinator program records which subsidiary program was last active.
To correctly implement fraction done, the main program should pass information to subsidiary programs (perhaps as command-line arguments) indicating the starting and ending fractions for that program.
The coordinator must call
void boinc_child_start();
prior to forking a child process.
When the child is done, the coordinator
must get the child's CPU time, then call
void boinc_child_done(double total_cpu);
before forking the next child process.
";
page_tail();
?>