commit 4b785f69c0616dba5d3f38e8ce4b5398cec89407
author Bram Moolenaar <Bram@vim.org> Tue Nov 29 21:54:44 2016 +0100
committer Bram Moolenaar <Bram@vim.org> Tue Nov 29 21:54:44 2016 +0100
tree fea8b654714ff391135ce61da9c9d0792b7a5265
parent f422bcc7f9615fe91fa69b059cfe4785093d3d4a

patch 8.0.0105
Problem:    When using ch_read() with zero timeout, can't tell the difference
            between reading an empty line and nothing available.
Solution:   Add ch_canread().

src/evalfunc.c

diff --git a/src/evalfunc.c b/src/evalfunc.c
index 846a914..88e4852 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -76,6 +76,7 @@
 static void f_ceil(typval_T *argvars, typval_T *rettv);
 #endif
 #ifdef FEAT_JOB_CHANNEL
+static void f_ch_canread(typval_T *argvars, typval_T *rettv);
 static void f_ch_close(typval_T *argvars, typval_T *rettv);
 static void f_ch_close_in(typval_T *argvars, typval_T *rettv);
 static void f_ch_evalexpr(typval_T *argvars, typval_T *rettv);
@@ -499,6 +500,7 @@
     {"ceil",		1, 1, f_ceil},
 #endif
 #ifdef FEAT_JOB_CHANNEL
+    {"ch_canread",	1, 1, f_ch_canread},
     {"ch_close",	1, 1, f_ch_close},
     {"ch_close_in",	1, 1, f_ch_close_in},
     {"ch_evalexpr",	2, 3, f_ch_evalexpr},
@@ -1779,6 +1781,21 @@
 
 #ifdef FEAT_JOB_CHANNEL
 /*
+ * "ch_canread()" function
+ */
+    static void
+f_ch_canread(typval_T *argvars, typval_T *rettv)
+{
+    channel_T *channel = get_channel_arg(&argvars[0], TRUE, TRUE, 0);
+
+    rettv->vval.v_number = 0;
+    if (channel != NULL)
+	rettv->vval.v_number = channel_has_readahead(channel, PART_SOCK)
+			    || channel_has_readahead(channel, PART_OUT)
+			    || channel_has_readahead(channel, PART_ERR);
+}
+
+/*
  * "ch_close()" function
  */
     static void