Refinement per @vtjnash comments.

Make uv_write() a function (was a macro) and do c_free in "finally" clause.

Explicit null-termination in jl_safe_printf() to allow for win32's
non-posix vsnprintf behaviour. See also JuliaLang#9624.

Use jl_safe_printf() in profile thread.

Send help message to jl_printf(JL_STDOUT,)  was stderr.

base/stream.jl

@@ -725,26 +725,27 @@ end
 # finish_read(state...)
 #end
 
-macro uv_write(stream, data, len)
- esc(quote
-  check_open(s)
-  uvw = c_malloc(_sizeof_uv_write)
+function uv_write(s::AsyncStream, p, n::Integer)
+ check_open(s)
+ uvw = c_malloc(_sizeof_uv_write)
+ try
  uv_req_set_data(uvw,C_NULL)
  err = ccall(:jl_uv_write,
  Int32,
  (Ptr{Void}, Ptr{Void}, UInt, Ptr{Void}, Ptr{Void}),
- handle($(stream)), $(data), $(len), uvw,
+ handle(s), p, n, uvw,
  uv_jl_writecb_task::Ptr{Void})
  if err < 0
- c_free(uvw)
  uv_error("write", err)
  end
  ct = current_task()
  uv_req_set_data(uvw,ct)
  ct.state = :waiting
  stream_wait(ct)
+ finally
  c_free(uvw)
- end)
+ end
+ return n
 end
 
 ## low-level calls ##
@@ -754,17 +755,14 @@ write(s::AsyncStream, c::Char) = write(s, string(c))
 function write{T}(s::AsyncStream, a::Array{T})
  if isbits(T)
  n = uint(length(a)*sizeof(T))
- @uv_write s a n
- return int(n)
+ return uv_write(s, a, n);
  else
  check_open(s)
  invoke(write,(IO,Array),s,a)
  end
 end
-function write(s::AsyncStream, p::Ptr, n::Integer)
- @uv_write s p n
- return int(n)
-end
+
+write(s::AsyncStream, p::Ptr, n::Integer) = uv_write(s, p, n)
 
 function _uv_hook_writecb_task(s::AsyncStream,req::Ptr{Void},status::Int32)
  d = uv_req_data(req)

src/jl_uv.c

@@ -605,13 +605,15 @@ int jl_printf(uv_stream_t *s, const char *format, ...)
 DLLEXPORT void jl_safe_printf(const char *fmt, ...)
 {
  static char buf[1000];
+ buf[0] = '\0';
 
  va_list args;
  va_start(args, fmt);
  // Not async signal safe on some platforms?
  vsnprintf(buf, sizeof(buf), fmt, args);
  va_end(args);
 
+ buf[999] = '\0';
  write(STDERR_FILENO, buf, strlen(buf));
 }
 

src/profile.c

@@ -218,7 +218,7 @@ void *mach_profile_listener(void *arg)
  bt_size_cur += rec_backtrace_ctx_dwarf((ptrint_t*)bt_data_prof+bt_size_cur, bt_size_max-bt_size_cur-1, &uc);
  }
  else if (forceDwarf == -1) {
- jl_printf(JL_STDERR, "Warning: Profiler attempt to access an invalid memory location\n");
+ jl_safe_printf("Warning: Profiler attempt to access an invalid memory location\n");
  }
 
  forceDwarf = -2;

src/task.c

@@ -739,7 +739,7 @@ DLLEXPORT void gdblookup(ptrint_t ip)
  if (line_num == ip)
  jl_safe_printf("unknown function (ip: %d)\n", line_num);
  else if (line_num == -1)
- jl_safe_printf("%s at %s (unknown line)\n", func_name, file_name, line_num);
+ jl_safe_printf("%s at %s (unknown line)\n", func_name, file_name);
  else
  jl_safe_printf("%s at %s:%d\n", func_name, file_name, line_num);
  }

ui/repl.c

@@ -139,7 +139,7 @@ void parse_opts(int *argcp, char ***argvp)
  jl_compileropts.cpu_target = strdup(optarg);
  break;
  case 'h':
- jl_printf(JL_STDERR, "%s%s", usage, opts);
+ jl_printf(JL_STDOUT, "%s%s", usage, opts);
  jl_exit(0);
  case 'O':
  jl_compileropts.opt_level = 1;