diff --git a/Makefile.msc b/Makefile.msc
index 62c87cb594..23fb546649 100644
--- a/Makefile.msc
+++ b/Makefile.msc
@@ -2743,6 +2743,9 @@ rbu.exe:	$(TOP)\ext\rbu\rbu.c $(TOP)\ext\rbu\sqlite3rbu.c $(SQLITE3C) $(SQLITE3H
 	$(LTLINK) $(NO_WARN) -DSQLITE_ENABLE_RBU \
 		$(TOP)\ext\rbu\rbu.c $(SQLITE3C) /link $(LDFLAGS) $(LTLINKOPTS)
 
+$(AUXTEST).exe:	$(TOP)\test\c\$(AUXTEST).c
+	$(LTLINK) $(NO_WARN) $(TOP)\test\c\$(AUXTEST).c sqlite3.lo /link $(LDFLAGS) $(LTLINKOPTS)
+
 THREADTEST3_SRC = \
   $(TOP)\test\threadtest3.c \
   $(TOP)\test\tt3_checkpoint.c \
diff --git a/main.mk b/main.mk
index e6cff6b0a2..97ff3798e9 100644
--- a/main.mk
+++ b/main.mk
@@ -2427,6 +2427,10 @@ sqlite3session.o:	$(TOP)/ext/session/sqlite3session.c $(DEPS_EXT_COMMON)
 stmt.o:	$(TOP)/ext/misc/stmt.c $(DEPS_EXT_COMMON)
 	$(T.cc.extension) -c $(TOP)/ext/misc/stmt.c
 
+$(AUXTEST): $(TOP)/test/c/$(AUXTEST).c
+	$(T.cc.sqlite) -o $@ $(TOP)/test/c/$(AUXTEST).c sqlite3.o $(LDFLAGS.libsqlite3)
+
+
 #
 # Windows section
 #
diff --git a/manifest b/manifest
index 2b3931afff..17c0b210d2 100644
--- a/manifest
+++ b/manifest
@@ -1,12 +1,12 @@
-C The\ssqlite3_str_new()\sinterface\snever\sreturns\sNULL,\seven\safter\san\sOOM.\nCode\sthat\suses\sthat\sinterface\sshould\sinvoke\ssqlite3_str_errcode()\sto\ssee\nif\san\sOOM\shas\soccurred.
-D 2026-04-15T14:41:25.480
+C Run\sC-language\stests\sin\stests/c/\sas\spart\sof\srelease\stest.
+D 2026-04-16T16:43:32.721
 F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md 6bc480fc673fb4acbc4094e77edb326267dd460162d7723c7f30bee2d3d9e97d
 F Makefile.in 5fda086f33b144da08119255da1d2557f983d0764a13707f05acf0159fd89ba5
 F Makefile.linux-generic bd3e3cacd369821a6241d4ea1967395c962dfe3057e38cb0a435cee0e8b789d0
-F Makefile.msc 5f54de6ee82c2401f17bb0e1b9051466d6cc131c7a99fa3e0005ca02eae27e1c
+F Makefile.msc 6f4294982758b5eeeac740c1a263186c3fcb9ba51d1b48261e321bcb37a41dbb
 F README.md e4f1a030f813c2fafc898c66d4f10bff2c75eb1a8f504eb9ad9a5ef80e3ff814
 F VERSION 99cf3be5f13d091183e4314b7fc2e0c0e69accfbe64608b45a313338bbdd7b62
 F art/icon-243x273.gif 9750b734f82fdb3dc43127753d5e6fbf3b62c9f4e136c2fbf573b2f57ea87af5
@@ -657,7 +657,7 @@ F ext/wasm/tests/opfs/sahpool/index.html be736567fd92d3ecb9754c145755037cbbd2bca
 F ext/wasm/tests/opfs/sahpool/sahpool-pausing.js f264925cfc82155de38cecb3d204c36e0f6991460fff0cb7c15079454679a4e2
 F ext/wasm/tests/opfs/sahpool/sahpool-worker.js bd25a43fc2ab2d1bafd8f2854ad3943ef673f7c3be03e95ecf1612ff6e8e2a61
 F magic.txt 5ade0bc977aa135e79e3faaea894d5671b26107cc91e70783aa7dc83f22f3ba0
-F main.mk f5283da2d8494486e72a6f49463d68c083201d7524433b914355ed716ec87ecc
+F main.mk d9cbbee974a8cd3999430130378878bd87b8c5754397a69ec322f4c9cc3e4e41
 F make.bat a136fd0b1c93e89854a86d5f4edcf0386d211e5d5ec2434480f6eea436c7420c
 F mptest/config01.test 3c6adcbc50b991866855f1977ff172eb6d901271
 F mptest/config02.test 4415dfe36c48785f751e16e32c20b077c28ae504
@@ -944,6 +944,8 @@ F test/btree02.test 7555a5440453d900410160a52554fe6478af4faf53098f7235f1f443d5a1
 F test/btreefault.test a82a23b0578bc587afbf9a622c8f54a54f63762f062ba8a35613cfee38ab42f9
 F test/busy.test caff7164c16ce06a53af51f9e4c2753d4cc64250e00790a5e48b9c4f4be37597
 F test/busy2.test 20823a5d7c42fb257d9f108c66312d90b1bb4ec3d80ba6b4e371073727560f98
+F test/c/malloc1.c 2869384011b5dc1f019ddd94e5248a1f2dfd07db06c6ce854793c91da173b811
+F test/c/snprintf1.c a66a1ce1195bd409740a60ebeea008686ce3fbacb445840fc0a45419823b7f3f
 F test/cache.test 13bc046b26210471ca6f2889aceb1ea52dc717de
 F test/cacheflush.test af25bb1509df04c1da10e38d8f322d66eceedf61
 F test/cachespill.test 895997f84a25b323b166aecb69baab2d6380ea98f9e0bcc688c4493c535cfab9
@@ -1607,7 +1609,7 @@ F test/selectG.test 089f7d3d7e6db91566f00b036cb353107a2cca6220eb1cb264085a836dae
 F test/selectH.test 0b54599f1917d99568c9b929df22ec6261ed7b6d2f02a46b5945ef81b7871aac
 F test/session.test 78fa2365e93d3663a6e933f86e7afc395adf18be
 F test/sessionfuzz-data1.db 1f8d5def831f19b1c74571037f0d53a588ea49a6c4ca2a028fc0c27ef896dbcb
-F test/sessionfuzz.c f693b8827034a3bed7616d89c65fb4fe8b7ff3c0f000c6ea6beda69b7f1aced3
+F test/sessionfuzz.c 0ec813258fbfd222c62ba6867c6a5a015f098fcaa6d89e7e0ee623ea91145cf0
 F test/shared.test 50bd8091735b272732125928c363476a17b5fb264835de7d19e90c72055c888b
 F test/shared2.test 03eb4a8d372e290107d34b6ce1809919a698e879
 F test/shared3.test cb92d083003ddf0f313166e494ec2fcafa55fdebf648628923ded3169dba8850
@@ -1716,8 +1718,8 @@ F test/temptrigfault.tes fc5918e64f3867156fefe7cfca9d8e1f495134a5229b2b511b0dc11
 F test/temptrigger.test a00f258ed8d21a0e8fd4f322f15e8cfb5cef2e43655670e07a753e3fb4769d61
 F test/tester.tcl 2d943f60200e0a36bcd3f1f0baf181a751cd3604ef6b6bd4c8dc39b4e8a53116
 F test/testloadext.c 862b848783eaed9985fbce46c65cd214664376b549fae252b364d5d1ef350a27
-F test/testrunner.tcl 3b6cbceb4d7f0226d51a7fde247cc5592565953568c18155c8c3a454d93bee71 x
-F test/testrunner_data.tcl 48c8a230fcada37f4809f95c2ba49e44bc3d520b6165c09173249c6e65b01cc1
+F test/testrunner.tcl cc5ff144daa48e351cf4523a45998986a1d68f85d5babfd53e372dc1a74f6fdc x
+F test/testrunner_data.tcl dfcf192d274e965845189cc014ac89fff91dde92b6e2ac9e1262897fc21ee2e0
 F test/testrunner_estwork.tcl 81e2ae10238f50540f42fbf2d94913052a99bfb494b69e546506323f195dcff9
 F test/thread001.test a0985c117eab62c0c65526e9fa5d1360dd1cac5b03bde223902763274ce21899
 F test/thread002.test c24c83408e35ba5a952a3638b7ac03ccdf1ce4409289c54a050ac4c5f1de7502
@@ -2199,8 +2201,9 @@ F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee
 F tool/warnings.sh a554d13f6e5cf3760f041b87939e3d616ec6961859c3245e8ef701d1eafc2ca2
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
 F tool/winmain.c 00c8fb88e365c9017db14c73d3c78af62194d9644feaf60e220ab0f411f3604c
-P 92d8ac0c4938e43b00111b43630ecfa91c30e5200ca03937a84f4b50bd1a13b3
-R 2044f397ccfeb7d1bf77600ef85df643
-U drh
-Z e3131e0c1c5850c27f08aad1e0cda310
+P cb910047edc591102dd4ed0d57c863b366981b8aa1d3085d5f95b1fbbabf6c31 2d81ee65ffbed30fd98bdda96dc79c1929c73f806cea3c9e4c244b618980b202
+R be1926b5db74f71941439938d0fcffd3
+T +closed 2d81ee65ffbed30fd98bdda96dc79c1929c73f806cea3c9e4c244b618980b202
+U dan
+Z cac81702445eb1f77e03aa0851674706
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 3edd99b2e1..d9e20ced73 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-cb910047edc591102dd4ed0d57c863b366981b8aa1d3085d5f95b1fbbabf6c31
+e6929022b71c6bff7aa9cfbdb8a5e80499ca856b8c06d4211c55311b48704a08
diff --git a/test/c/malloc1.c b/test/c/malloc1.c
new file mode 100644
index 0000000000..16d8455894
--- /dev/null
+++ b/test/c/malloc1.c
@@ -0,0 +1,14 @@
+
+#include "sqlite3.h"
+#include <stdio.h>
+
+int main(void) {
+  void *p = 0;
+#ifdef SQLITE_OMIT_AUTOINIT
+  sqlite3_initialize();
+#endif
+  p = sqlite3_malloc(32);
+  if( !p ) return 1;
+  sqlite3_free(p);
+  return 0;
+}
diff --git a/test/c/snprintf1.c b/test/c/snprintf1.c
new file mode 100644
index 0000000000..859cf3c9d7
--- /dev/null
+++ b/test/c/snprintf1.c
@@ -0,0 +1,18 @@
+#include "sqlite3.h"
+#include <stdio.h>
+
+int main(void) {
+  const char *zExpect = "2023.000";
+  char szBuffer[32];
+  double val = 2023.0;
+#ifdef SQLITE_OMIT_AUTOINIT
+  sqlite3_initialize();
+#endif
+  sqlite3_snprintf(17, szBuffer, "%.3f", val);
+  printf("size 17: '%s'\n", szBuffer);
+  if( sqlite3_stricmp(zExpect, szBuffer) ) return 1;
+  sqlite3_snprintf(16, szBuffer, "%.3f", val);
+  printf("size 16: '%s'\n", szBuffer);
+  if( sqlite3_stricmp(zExpect, szBuffer) ) return 1;
+  return 0;
+}
diff --git a/test/sessionfuzz.c b/test/sessionfuzz.c
index c389a5e996..b8ac7bcb16 100644
--- a/test/sessionfuzz.c
+++ b/test/sessionfuzz.c
@@ -882,6 +882,10 @@ int main(int argc, char **argv){
   int nChgset;
   int bVerbose = 0;
 
+#ifdef SQLITE_OMIT_AUTOINIT
+  sqlite3_initialize();
+#endif
+
   if( argc<2 ){
     fprintf(stderr, "%s", zHelp);
     exit(1);
diff --git a/test/testrunner.tcl b/test/testrunner.tcl
index 4d1ba57f38..ab6e6e20ea 100755
--- a/test/testrunner.tcl
+++ b/test/testrunner.tcl
@@ -1298,6 +1298,57 @@ proc add_build_job {buildname target {postcmd ""} {depid ""}} {
   list $id [file normalize $dirname] $buildname
 }
 
+# Add jobs to build and run all the *.c files in $testdir/c/ for build
+# configuration $buildname.
+# 
+proc add_c_jobs {buildname} {
+  global TRG
+
+  set dir [file join $::testdir c]
+
+  # One job to build the sqlite3.o file for this configuration. Each
+  # individual "c" job will copy this sqlite3.o into its working directory
+  # so that it doesn't have to build it separately every time. 
+  #
+  set obj sqlite3.o
+  if {$TRG(platform)=="win"} { set obj sqlite3.lo }
+  set B [add_build_job $buildname $obj]
+  foreach {bldid blddir dummy} $B {}
+
+  # One job for each C file.
+  #
+  foreach f [glob -nocomplain $dir/*.c] {
+    set prg [string range [file tail $f] 0 end-2]
+
+    set cmd ""
+    if {$TRG(platform)=="win"} {
+      foreach cp {sqlite3.lo *.h *.c} {
+        append cmd "copy [file nativename [file join $blddir $cp]] .\n"
+      }
+      append cmd "SET AUXTEST=$prg\n"
+      set prg "${prg}.exe"
+      append cmd "$TRG(makecmd) $prg\n"
+      append cmd ".\\$prg\n"
+    } else {
+      set cmd "set -e\n"
+      foreach cp {sqlite3.c sqlite3.h sqlite3.o .target_source src-verify} {
+        append cmd "cp [file join $blddir $cp] .\n"
+      }
+      append cmd "AUXTEST=$prg $TRG(makecmd) $prg\n"
+      append cmd "./$prg\n"
+    }
+    
+    set id [add_job                                \
+      -displaytype tcl                             \
+      -displayname "$prg ($buildname)"             \
+      -build $buildname                            \
+      -cmd  $cmd                                   \
+      -depid $bldid                                \
+      -priority 3
+    ]
+  }
+}
+
 proc add_shell_build_job {buildname dirname depid} {
   global TRG
 
@@ -1545,6 +1596,8 @@ proc add_jobs_from_cmdline {patternlist} {
             UPDATE jobs SET depid=$sbldid WHERE depid='SHELL'
           }
         }
+
+        add_c_jobs $b
       }
     }
 
diff --git a/test/testrunner_data.tcl b/test/testrunner_data.tcl
index 57ab054438..a30402826c 100644
--- a/test/testrunner_data.tcl
+++ b/test/testrunner_data.tcl
@@ -143,6 +143,7 @@ namespace eval trd {
     -DSQLITE_ENABLE_UNLOCK_NOTIFY
     -DSQLITE_THREADSAFE
     -DSQLITE_TCL_DEFAULT_FULLMUTEX=1
+    -DSQLITE_OMIT_AUTOINIT=1
   }
   set build(Secure-Delete) {
     -O2